It is well known to form coreless paper roll products such as rolls of toilet tissue on winder mandrels or shafts. Arrangements of this type are disclosed, for example, in U.S. Pat. No. 3,853,279, issued Dec. 10, 1974, U.S. Pat. No. 3,856,226, issued Dec. 24, 1974, U.S. Pat. No. 5,271,137, issued Dec. 21, 1993, and U.S. Pat. No. 5,271,575, also issued on Dec. 21, 1993.
Coreless tissue rolls are finding increased acceptance in the marketplace. By not employing a conventional roll core of paperboard or the like, more tissue can be incorporated in the roll for any given diameter. Furthermore, there is essentially no product waste as compared to conventional arrangements wherein the core of paperboard or other material must be discarded after use.
A problem does present itself with regard to coreless tissue rolls in that the aperture or hole passing through the center of the roll can lose definition, making it difficult, if not impossible, for a dispenser spindle to be inserted into a roll end.
As is disclosed in detail below, the present invention solves this problem by wetting the coreless paper roll at the ends thereof, and only at the ends thereof, during manufacture, i.e. while the coreless paper roll product is being formed on a rotating winder shaft. When the roll product is removed from the shaft, the ends will generally retain the shape of the winder shaft and not collapse, thus allowing ready insertion of a dispenser spindle to allow use by a consumer.
It is known in the prior art to form the central core of a toilet paper roll by winding the advancing or lead end of a paper web between rolls having corrugated peripheries and at the same time applying glue or paste to the paper web so that the web is initially wound upon a corrugated mandrel and pressed into a multi-ply corrugated roll upon which the web may be further wound without the application of glue, the result being a finished toilet roll package having a corrugated roll.
U.S. Pat. No. 1,882,012, issued Oct. 11, 1932, discloses the system just described. The problem with this prior art approach is that one still can not dispense and utilize all of the paper. The core still must be discarded, resulting in material waste.
U.S. Pat. No. 4,487,378, issued Dec. 11, 1984, discloses a coreless toilet paper roll having a center hole which is formed by winding toilet paper on a winding shaft having a polygonal or gear-shaped cross-section and then extracting the polygonal or gear-shaped winding shaft from the roll. The special shafts employed when practicing the method of this invention are quite expensive as compared to round mandrels or winding shafts.
In contrast to the approach disclosed in U.S. Pat. No. 5,271,575, the present invention provides for a stable entry hole in a coreless paper roll without the necessity of employing an expensive specially-shaped winding shaft. The present approach utilizes a round winder shaft which is inexpensive, readily available, and can be utilized with commercially available re-winder equipment.
U.S. Pat. No. 4,783,015, issued Nov. 8, 1988, discloses a toilet paper roll which is devoid of a paperboard core and has a two-layered structure comprising a hard core layer portion formed by tightly rolling up toilet paper on a temporary take-up core which is eventually removed and an outer layer portion formed continuous to the core layer portion by rolling up the toilet paper less tightly than the core layer portion. The approach requires specialized, expensive equipment and hard winding of the inner layers of the roll can not only diminish the softness and other desirable physical characteristics thereof but also actually promote collapse of the center hole due to the tight winding of the inner convolutions. Furthermore, tight winding can make the roll inapplicable for use with certain types of spindles, particularly spindles having a cross-section greater in magnitude than that of the central roll aperture.
As noted above, the present invention incorporates the step of applying a liquid only at the ends of a roll during formation thereof. It is known in the prior art to apply a liquid between a mandrel and the leading end of a tissue web to be wound thereon to secure the end of the tissue to the mandrel. Such an arrangement is illustrated in U.S. Pat. No. 3,823,887, issued Jul. 16, 1974. In this prior art arrangement, the tissue web end and mandrel are wetted along the entire length thereof. Although not described with clarity in the patent, wetting appears to be accomplished by means of a wet sponge 74 impressed onto the mandrel and leading end of the tissue web along the full width of the web. Since the completed roll product is wetted in the interior thereof along the full roll length, application of liquid can result in bonding of a significant number of convolutions of the roll and thus make such convolutions unavailable for use.
Another patent of interest is U.S. Pat. No. 5,281,386, issued Jan. 25, 1994, wherein a probe element is inserted in a coreless paper roll end and liquid inserted into the roll end through the probe to change hole shape after roll formation.
Other patents of some relevance to the present invention of which applicant is aware are the following: U.S. Pat. No. 1,930,250, issued Oct. 10, 1933, U.S. Pat. No. 4,895,315, issued Jan. 23, 1990, U.S. Pat. No. 1,880,448, issued Oct. 4, 1932, U.S. Pat. No. 610,339, issued Sep. 6, 1898, and U.S. Pat. No. 309,332, issued Dec. 16, 1884.